according to haynes manual and the data book (thanks to information gathered here and information from members) valve clearance is of 0.25mm (10 thou) intake, and 0.20mm(8 thou) exhaust.

testing with diferent valve clearance affect fuel economy

Edited 28 December, 200817 yr by Cepheuz

Ok, nice to read.

BUT: Valve clearence should depend on the local environment. 0,20|0.20 is only suitable for warmer regions because the expansion is less.

For european standard exhaust should be more.

It also depends on carburator or injection. The fuel economy of 0.20|0.25 (in|out) isn't that worse at injection models.

Ok, nice to read.

BUT: Valve clearence should depend on the local environment. 0,20|0.20 is only suitable for warmer regions because the expansion is less.

For european standard exhaust should be more.

It also depends on carburator or injection. The fuel economy of 0.20|0.25 (in|out) isn't that worse at injection models.

i'm in the Caribbean, warm weather year round, and i find it logical that the 0.25mm reading should be less cause of the metal expanding less,

Edited 28 December, 200817 yr by Cepheuz

my expert had the same engine and he tried it the same way as you did and is result was the larger exhaust value.

the exhaust should be larger 'cause it hast to bear a larger temperature spectrum.

and why should inlet be larger than exhaust? exhaust becomes hotter....

i set them to 0.23 and already one of the plugs is showing fouling (#2, 4th in detonation cycle) so that tell me its not sitting right that tells me that anything less than 0.25 on the exhaust is going to cause problems on my engine

and i do agree that climate temperature has to be taken into consideration the engine block never get colder than 23 degrees here where as in Europe it can reach the teens.

guess i have to go back to 0.25 all around and i might go as far as putting them 0.28mm to make sure they're sitting properly (all thou i'll have a car powered by a typewriter, jejeje)

Edited 28 December, 200817 yr by Cepheuz

what do you mean with fouling?

at this thread

the inlets have a larger gap because they have alloy pushrods which expand more than the steel exhaust ones

sorry but why are you rofling? i think ten years of skoda motorsport experiences are enough...

what do you mean with fouling?

fouling is anything that covers the spark plug, it can come from unburned gasoline (black powder) pre-detonation (sand like particles) bad mix / too rich (creamish looking powder) oil (dark coffee look) unburned fuel additives (creamy glaze on the ceramic) etc...

Edited 28 December, 200817 yr by Cepheuz

at this thread

the inlets have a larger gap because they have alloy pushrods which expand more than the steel exhaust ones

that's true, but i'm seriously thinking of changing 4 of them so they are the same alloy and have my way with valve clearances is a stupid mod (buy pushrods remove valve train take out pushrods, inspec them and put them back in replacing different ones with new ones refit vlve trail and adjust valve clearances this time slightly less gap) that should only take 45 min to complete

sorry but why are you rofling? i think ten years of skoda motorsport experiences are enough...

that deserves 3 :rofl:

Why mess about changing the pushrods when you've already proved in your first post that the original clearances give the best compromise of torque/MPG?

I know you're trying to help us mate, but this is all a little pointless. Removing the rocker shaft to change the pushrods involves undoing 2 head bolts so you might end up having to replace the head gasket. This is so that you can change the clearances again from the manufacturers recommended settings which you have already proved are the best compromise? Not only that, but adjusting your valve clearances every other day will just mean you'll end up wearing out all your adjusters! They only need setting every 10,000 miles! These old engines are pretty crude really, so I doubt that a valve clearance

difference of 0.05mm will make a huge difference to anything.

No offence meant mate, just trying to save you some hassle. We appreciate your experiment has been done to help us, and have learnt that the original clearances are best. Thank you.

Why mess about changing the pushrods when you've already proved in your first post that the original clearances give the best compromise of torque/MPG?

I know you're trying to help us mate, but this is all a little pointless. Removing the rocker shaft to change the pushrods involves undoing 2 head bolts so you might end up having to replace the head gasket. This is so that you can change the clearances again from the manufacturers recommended settings which you have already proved are the best compromise? Not only that, but adjusting your valve clearances every other day will just mean you'll end up wearing out all your adjusters! They only need setting every 10,000 miles! These old engines are pretty crude really, so I doubt that a valve clearance

difference of 0.05mm will make a huge difference to anything.

No offence meant mate, just trying to save you some hassle. We appreciate your experiment has been done to help us, and have learnt that the original clearances are best. Thank you.

simple... i do and will put the manufactures specified setting, but in order to do that i must first undo the mistake that the old mechanic did.

and i was messing every other day with the valves cus i knew the problem was there, if i would have know sooner that the push rods where place incorrectly, i would have just done the job 1 time needed and thats it.

and yes, i know i would have to change the head gasket, but you guys get above 45km/g (28mpg 8.4L /100km) and i'm getting at best 36km/g (22mpg 10.5L /100K) so i know that my problem is real, and you can imagine how much money i'm having to shell out driving 40km per day.

every other aspect of increasing fuel economy has been address, including going back to stock 165/70R13 tires

again, thanks to my digging i found what the problem was (those mechanics here dont know what there doing) and i will address the problem cus i dont want ot go by another car just cus i got the fuel economy problem

oh, and by the way, if i had the money to have a certified mechanic inspect the engine and have it fix i would have from the begging ok, but i simply don't have the fund and must make due with my ingenuity

i doubt u have to back out any head bolts........ just loosen each tappet slide the push rod to the side... pull them out ........ inspect them ......... replace them then tighten back down to what ever valve clearance u want.......

i doubt u have to back out any head bolts........ just loosen each tappet slide the push rod to the side... pull them out ........ inspect them ......... replace them then tighten back down to what ever valve clearance u want.......

going to try to do that if not i'll have to shell out RD$4,800 (96.80 Euros) to have the house remove it and in order to offer guarantee they have to check the hole system, that means i have to buy parts needed :S

oh and daverapid, i'm using 115liters of fuel (average) a month driving about 30km on average per day opposed to 75liters if i get the estimated on spec (8.6l/100) and 58.5liters if i get values like polliwog on summer...

put a little math on those figures and imagine what i have to shell out on the gas station compare to what i could be saving if my push rods where o.k. and i could set the correct valve clearances...

do you still find it pointless ?

do you now understand why i had to test different configurations to find the problem?

what would you do, and please if you know more about mechanic, on anyone, please tell me, cus you be doing me a huge favor if you can point me to a solution that doesn't involve shelling out 96 euros + parts ( if you think thats not expensive consider i earn 279 euros a month and have to deal with living expensive and gas)

so please, please, please i implore anyone, help me out instead of looking down at my attempts to find a solution

No matter how bad your valve clearances are they shouldn't be causing such a drastic difference in economy.

Which engine is your car (exactly). Also what do you mean when you say the push rods weren't installed correctly, do you mean the inlets and exhausts were mixed up? If so are you 100% certain? Very few (but some) engines run I-E-I-E-I-E-I-E indeed most have siamesed or at least side by side ports usually something like E-I-I-E-E-I-I-E find out because chances are your rods aren't placed incorrectly. Even if they are it really isn't the end of the world, are felicia valve clearances set hot or cold? If hot (which is common) then you won't be getting issues of the alloy rods expanding more than the steel rods and causing your valves to stay open when hot as you will be setting them when hot, if you set them when cold then check them when hot and see if there is a gap there or not, 10-15thou will see most engines pretty well.

If you are getting poor economy far more likely is an ignition or fueling problem, is your timing set correctly? Is your mixture correct? Forget this nonsense about vacuum it is of absolutely no use to you at all, by all means compression test your cylinders this will give you an accurate impression of the condition of your engine, but vacuum gauges are only of use to set up multiple carbs (same job can be done with a bit of tube and your ear anyway) and as a pretty gauge that flickers around on your dash. Waste of time for anything else. Get your mixture checked (with a CO meter if you have access, a colourtune "glass" sparkplug is as good as anything though for the home mechanic.) and get your timing checked. I doubt your car does have points but if it does check them and replace if needed they do have a direct effect on timing.

I repeat forget about your rods they really aren't causing you the problem you believe, if after all that the engine is set up properly (as per manufacturer) and you are still getting poor MPG then I would suggest that assuming the engine isn't badly worn (compression test), assuming you are running the correct tyre pressure, your handbrake in particular but all brakes aren't binding and your gearbox has oil in it then the problem is your driving it too hard.

No matter how bad your valve clearances are they shouldn't be causing such a drastic difference in economy.

Which engine is your car (exactly). Also what do you mean when you say the push rods weren't installed correctly, do you mean the inlets and exhausts were mixed up?

Yup!, that's exactly why i had to mess around so much cus i was setting the clearance cold

If so are you 100% certain? Very few (but some) engines run I-E-I-E-I-E-I-E indeed most have siamesed or at least side by side ports usually something like E-I-I-E-E-I-I-E find out because chances are your rods aren't placed incorrectly.

E - I - I - E - E - I - I - E valve placement cylinder firing order is 1-4-2-3

Even if they are it really isn't the end of the world, are felicia valve clearances set hot or cold?

setting them cold, dead cold, but thank for the tip on setting them hot, if i would have know that i would have done it in the begining and save a lot of trouble

If hot (which is common) then you won't be getting issues of the alloy rods expanding more than the steel rods and causing your valves to stay open when hot as you will be setting them when hot, if you set them when cold then check them when hot and see if there is a gap there or not, 10-15thou will see most engines pretty well.

to make sure i'll monitor car efficiency and fuel usage and check it hot in a couple of days

If you are getting poor economy far more likely is an ignition or fueling problem, is your timing set correctly?

yes, very accustom on setting it with a vacuum for tuning, but strobe light is always used for diagnostics and to be 100% is the manufactures setting, i double checked the ignition coil, HT and dizzy and they are all good, have crisp BOSH spark plugs gapped to 0.80mm and vacuum advance is working correctly

Is your mixture correct?

if not correct is close as possible, don't have access to a CO meter, but i leaned the mix until idle got rough and enriched by 1/4 turn. if i remove a vacuum hose, engine does not accelerate or decrease idle, only start to idle rough, and no overheating or pinging

by all means compression test your cylinders this will give you an accurate impression of the condition of your engine,

did that after setting the valves to 0.25mm all around and all cylinders where ok

Get your mixture checked (with a CO meter if you have access, a colourtune "glass" sparkplug is as good as anything though for the home mechanic.)

don't have access to one, but my spark plugs read o.k. with the timing but coloration on the ceramic is different across all and #2 showed fouling (before was #1 and when i set valves all to 0.25mm none had fouling) and no my car doesn't have point, it has a ignition and a coil with the dizzy. coil has been replace and test with a voltmeter and ignition module replaced by a new one.

tires are 165/70R13 stock alloy rims 32 (2.0) pressure

up shift@ 2000rpm down shift@ 600rpm

no heavy acceleration (grandma style suit me best and if you ever come to this country you'll know why { everybody drives like a maniac so its better to let them pass and take it easy}) car has no load in the trunk, brakes are o.k.

no vacuum lines have leaks

gasoline used is 4 parts regular (88ROZ) 6 parts premium (95ROZ) with Xp³ additive

Xp3 Fuel Additive

15W40 SAE Mobil1 engine oil 75W90 Mobil1 trans oil

no oil leaks or water leaks, exhaust with no fumes or smoke

any other suggestions or idea are very welcome, but now that i'm 100% sure of valves (and have a way of measuring them in hot) i guess we can eliminate that as a culprit..

fresh air, fuel and oil filters

and thanks wildoliver, if you ever need a grease monkey assistant restoring those cars give me a call, i'll do it for free just to be close to those beauty's and the knowledge

No worries, the colour your looking for on plugs is a biscuit colour (halfway between cream and brown) it should also look crisp and dry. However it is worth noting that the method to test plugs is a long straight road (a mile or so at least) drive the car at steady throttle (in the range you want to test, in your case your general driving throttle) then turn the ignition off while still travelling at that steady speed and stop. Pull the plugs and inspect. You have to stop the engine while running or you will be plug testing the engine at idle, if it is rich or weak at idle it will disguise the reading.

I'll be honest my suspicion would be your running a little weak, if you pull a (small) vacuum hose off does the engine noticably drop in revs or go lumpy? Or does it pick up speed? As a side note slightly obscure the carb choke with a hand (not totally cover about 25% of the opening across all the chokes equally) does the engine speed rise or drop?

Also has your car got a manual choke or is it automatic? If it's automatic chances are it is staying on (common fault on all carbs with them) you will have to resolve the issue (usually with a manual conversion kit or new carb) before going any further.

No worries, the colour your looking for on plugs is a biscuit colour (halfway between cream and brown) it should also look crisp and dry. However it is worth noting that the method to test plugs is a long straight road (a mile or so at least) drive the car at steady throttle (in the range you want to test, in your case your general driving throttle) then turn the ignition off while still travelling at that steady speed and stop. Pull the plugs and inspect. You have to stop the engine while running or you will be plug testing the engine at idle, if it is rich or weak at idle it will disguise the reading.

I'll be honest my suspicion would be your running a little weak, if you pull a (small) vacuum hose off does the engine noticably drop in revs or go lumpy? Or does it pick up speed? As a side note slightly obscure the carb choke with a hand (not totally cover about 25% of the opening across all the chokes equally) does the engine speed rise or drop?

Also has your car got a manual choke or is it automatic? If it's automatic chances are it is staying on (common fault on all carbs with them) you will have to resolve the issue (usually with a manual conversion kit or new carb) before going any further.

again, thank you for the quick reply, i'll answer as best as i can

yes, spark plug reading have been made in two stages, idle (850rpm) for 15min AND

normal road driving (no inclines or declines) for 2km then shut off, coast on neutral and inspect plugs.

color i'm looking for is teeth(smoker) looking white or just imagine a spark plug submerge in tea. with a crown of 0.20mm in the apex of the ceramic, slight coloring on the base and change in color in the apex of the ground strap and a small yellowish or bluish (depending on plugs heat rating) 1/4 of an inch away from the apex of the ground strap

i'm trying to be specific so you can correct me in any mistakes,

as far as i see it ceramic has a slightly darker color (the ones that are not fouled) but no crown (sigh of pre detonation, incorrect timing or mix) the color change is right on the apex of the earth strap (sigh of correct timing) but no triangle for good idle timing (initial timing) but it was there before. and the ground strap and firing end are clean (sigh of good spark)

when i set the manufactures specified clearance i had #4 crisp and too clean, and #1 fouled totaly and the other two dirty (carbon build up) so to solve this i was trying to adjust the clearances to eliminate the problem without having to go 0.28mm all around the only two setting that showed no fouling was 0.25mm all around or 0.20mm intake, 0.25mm exhaust but with the latter plugs showed too dark of a reading on the ceramic and loosing heat

for having different readings in the spark plugs on all clearances options found in this site is where i discovered that my push rods where i'll placed, so i went back to the safe setting of 0.25mm where i had no fouling (but i know i dint have optimum performances) to save the valves from burning.

so to cap it off Good spark, good timing pre-detonation and decent mix = compression problem, as i tested the compression with the 0.25 all around(but i did not test it on the other clearances settings) and it was good, head gasket doesn't show faults (over heating, water level rising when accelerating, oil mixed with water etc...) and the rings don't show sighs of problem (smoke on the exhaust, over fouled plugs, petrol smelly oil, pressure coming out of the engine etc..) i deducted cylinder was loosing compression on the valves side...(when setting was not 0.25mm all around and plugs where getting over fouled)

i have to be honest so i will update all of this data in the next couple of days (friend shop that has the tools to check compression is close for holidays) and i will inform on spark readings tomorrow with the new valve settings and inspected push rods.

i know what you mean with the carburetor, the automatic choke is working perfectly and is not staying engaged after temp reaches 76 degrees is completely disengaged

oh, by the way, i have not yet fitted the missing thermostat that the previous owner's mechanic took out (common practice here and i have been even laugh at cus of my objections and remarks that it should not be done) cause they believe that is designed for colder weather and not for tropic weather.. since i don't have a MPi or a computer assisted motor i know i'm only loosing 10% maybe 15% fuel economy (so from standard 8.6 i should be getting 45km/g or 5ish from pollywog's 7.2 reading)

if i remove a small vacuum hose the engine does not increase rpm and does not go down either, it just goes lumpy to use your term and its not huge lumps like malt or oats, is more like mash potatoes(trying to make a graphic idea of a mechanical one is kinda weird )

carburetor has been cleaned with carb cleaner with a partial disassembly to get to the jets and all seals are checked and ok and DW-40 all moving parts to make sure none are sticking and earth connector has been replace for a thicker gauge copper wire and tested

if i manually engage the choke a little (same as placing my hand i guess) it goes down in rpm

hope i explained myself o.k., it's not my strong... and i apologize for the long explanation

Edited 29 December, 200817 yr by Cepheuz

oh and daverapid, i'm using 115liters of fuel (average) a month driving about 30km on average per day opposed to 75liters if i get the estimated on spec (8.6l/100) and 58.5liters if i get values like polliwog on summer...

put a little math on those figures and imagine what i have to shell out on the gas station compare to what i could be saving if my push rods where o.k. and i could set the correct valve clearances...

do you still find it pointless ?

do you now understand why i had to test different configurations to find the problem?

what would you do, and please if you know more about mechanic, on anyone, please tell me, cus you be doing me a huge favor if you can point me to a solution that doesn't involve shelling out 96 euros + parts ( if you think thats not expensive consider i earn 279 euros a month and have to deal with living expensive and gas)

so please, please, please i implore anyone, help me out instead of looking down at my attempts to find a solution

Mate, please don't think I'm looking down on you, in fact I applaud your determination to sort out your fuel economy issue. I'm a qualified mechanic/MOT tester with 20 years experience working with old Skodas and I'm struggling to see why your car's fuel consumption is still higher than it should be after all your efforts.

Do you ever get petrol smells? It's not unknown for the plastic fuel reservoir attatched to the side of the carb to leak...they don't always actually drip, but let air in and allow the fuel to evaporate. Is the carb flooding, maybe the float level needs setting or the needle valve is sticking. Are your fuel hoses in good order? If they are the old cloth covered type I'd replace them as small leaks with this type of hose are common as they age. Does your engine oil level go up? Pull out the dipstick and smell the oil, does it smell of fuel? If so your fuel pump diaghragm may be letting fuel leak into the sump.

I'm obviously only guessing as we all are because we haven't got the car in front of us,but those are the things I'd be checking after all your sterling work tuning the engine, as well as ensuring the brakes aren't binding. Also it's worth making sure the clutch isn't slippping...do the engine revs rise without the car actually accelerating when going up hills?

As I said before, I'm not looking down on you or your considerable efforts, just trying to help. I think that goes for all of us.

Mate, please don't think I'm looking down on you, in fact I applaud your determination to sort out your fuel economy issue. I'm a qualified mechanic/MOT tester with 20 years experience working with old Skodas and I'm struggling to see why your car's fuel consumption is still higher than it should be after all your efforts.

Do you ever get petrol smells? It's not unknown for the plastic fuel reservoir attatched to the side of the carb to leak...they don't always actually drip, but let air in and allow the fuel to evaporate. Is the carb flooding, maybe the float level needs setting or the needle valve is sticking. Are your fuel hoses in good order? If they are the old cloth covered type I'd replace them as small leaks with this type of hose are common as they age. Does your engine oil level go up? Pull out the dipstick and smell the oil, does it smell of fuel? If so your fuel pump diaghragm may be letting fuel leak into the sump.

I'm obviously only guessing as we all are because we haven't got the car in front of us,but those are the things I'd be checking after all your sterling work tuning the engine, as well as ensuring the brakes aren't binding. Also it's worth making sure the clutch isn't slippping...do the engine revs rise without the car actually accelerating when going up hills?

As I said before, I'm not looking down on you or your considerable efforts, just trying to help. I think that goes for all of us.

indeed, but i have it in front of me so a good idea and promptness to check can big of big help, and i don't have your experiences dude so you can imagine my frustration, of course i do a lot of things and post them, cus i want to make sure is a good idea or the right way to go,

and i know what you mean with the oil thing and the reservoir thing, thats the first thing i had to replace when i purchased the car, and no, oil smell (and tastes :s) like oil and the hose are in good order cus' when i replaced the reservoir thing (it was a seal and the pump that drives the accelerator enrichment) the first thing whe checked was the hoses cus i was getting a strong gas smell

now one quick question... in your experiences, how many km should i get out of a gallon of fuel and my odometer and trip meter are measured in Km, could it be the posibility that you have them in km and think is in miles (jesus i know it sound stupid but at this point i'm shooting at anything) cus captain sisko gets 41mpg and daverapid 37mpg and polliwog 7.8L / 100km (49mpg) and this is car is supposed to give me 60km/g stock (37 mpg, 6.3L / 100km) according to a couple of guy's but in the spec sheet it says 8.6L/100km (44km/g, 27mpg) and me with 30km/g (19mpg, 12.6L/100K) is insane, AND BEFORE IT WAS MUCH WORST!!!...

oh and by the way i freaking love that rapid, it freaking looks gorgeous

Right I think were getting somewhere at last.

You mention that the plugs are fouling at manufacturers settings.

Set them back to the setting they should be, then find the problem. Don't try to mask problems with fiddling. Now as to why the plugs are fouling it could be a few things.

1) Wrong heat rating. I have no idea which plugs should be used in a felicia engine, but find out and use those plugs (make and model.) classic example being on old british engines they just run better and cleaner on Champions, you can get an identical NGK but they just don't seem to run as well.

2) Engine burning oil. Is it using any oil over a thousand miles (1.5k)?

3) Running rich.

4) Weak spark. Poorly spark unit (might be coil, renix unit or coil pack depending on engine). May be dodgy leads with tired caps that don't make a good connection.

Those are the most likely culprits. Once again you really need to get the engine properly set up to factory settings.

Oh and test your thermostat in boiling water and providing it opens then refit it. Engines are designed to run with one, most engines run without a stat (or sleeve instead) will overheat around the back cylinder due to poor water flow. There is very little cooling benefit to removing it as when open they provide very little constriction. The next bit is where it gets interesting.

Removing the stat will mean the engine will warm up slower, the stat exists to allow the engine to quickly warm up the water jacket contained within it on starting, it then opens and mixes the warm water in the engine with cool water in rad. This allows the engine to get up to temp much quicker.

If your running without the stat then the choke will be staying out longer, the engine will be running cold (inefficient) longer and you will use more fuel. You will also be running a richer mixture for longer which will eventually wash your bores accelerating wear. If your only driving 30km a day I seriously doubt your engine is getting properly up to temp at all, in which case that's the reason your getting poor economy.

Put it back in.